mineral

Howlite

Ca2B5SiO9(OH)5

Mohs hardness of 3.5, white or milky color with distinctive dark grey or black web-like veins, sub-vitreous to earthy luster, monoclinic crystal system, no distinct cleavage.

Identified July 31, 2026More mineral →

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Physical properties

Mohs hardness of 3.5, white or milky color with distinctive dark grey or black web-like veins, sub-vitreous to earthy luster, monoclinic crystal system, no distinct cleavage.

Formation & geological history

Formed as borate minerals in evaporite deposits, typically in sedimentary environments where boron-rich waters evaporate.

Uses & applications

Commonly used for ornamental carvings, beads, and cabochons in jewelry. Often dyed blue or green to imitate turquoise.

Geological facts

Howlite is extremely porous, which makes it very easy to dye. Because of this, it is frequently sold under trade names like 'turquoise-dyed howlite' or 'turquenite'.

Field identification & locations

Easily identified by its chalky white appearance and dark spiderweb matrix. Major deposits are found primarily in Nova Scotia, Canada, as well as the USA and South Africa.